Sunn Solarus tremolo bulb...?

[acorkos]

I am working on a Sunn Solarus, trying to restore the tremolo effect. I replaced all the electrolytics and transistors in the trem circuit, with no change. the LFO is oscillating and responding to the trem footswitch and the speed and depth controls...i can measure DC voltage across the bulb leads of the trem module...swings between ~4 volts and ~16 volts. I cut open the trem module and disassembled it, and then resolderd the LDR and bulb back to their original locations. the bulb doesn't respond to the voltages, so i'm asuuming it's dead. I swapped in a 24V grain of wheat bulb just to see what happens...it barely lit. but it did glow on and off along with the LFO. Anyone know of a good replacement for the bulb in this trem module? Or for a complete new trem module? Thanks for your help!

http://sunn.ampage.org/site/schematics/solarus.gif

[52 Bill]

Are you really reading 4-16 volts across the dead bulb terminals? What do you get across the working bulb?

The schematic shows 4.5 volts across the bulb. I would try a 6 volt bulb.

[acorkos]

i clipped my leads to the terminal strip where the bulb leads connect....4-16 volts whether a bulb, working or dead, is connected or not.

[52 Bill]

Well then, an 18 volt bulb will be safe. A 12 volt will probably work. I would have thought with the current draw of the bulb, that the voltage would be less than the supply voltage.

[acorkos]

no luck with the bulb...now i'm thinking about pulling out the solid state tremolo circuit, installing another 12AX7 and a bias vary trem circuit. good/bad idea? thanks for your reply!